OLL 17
The algorithm, how to recognise it and how to practise it without cheating.
Probability1/54
Moves13
TypeDot
Inverse and mirror—
Recommended algorithm
R U R' U R' F R F' U2 R' F R F'13 moves
How to recognise it
A dot with two opposite corners yellow on top. Hold them at back left and front right, with the front-left corner's yellow facing left.
Its inverse is another case
Do the 17 algorithm backwards, F R' F' R U2 F R' F' R U' R U' R', and you are solving 18.
That's why CubeDojo never scrambles 17 that way: it builds a random state with the case fixed, so you practise 17 and not 18.
Practise 17 now
Random-state scrambles, a timer and spaced review. Free, on the web and on your phone.